Food processing systems typically utilize pumps of various constructions to move the product through the system. One type of continuous pump using alternating pistons is disclosed in U.S. Pat. No. 3,456,285 issued Jul. 22, 1969, and U.S. Pat. No. 4,097,962 issued Jul. 4, 1978, both of which are owned by the Assignee of the present invention. The '285 patent and the '962 patent are hereby incorporated by reference into this specification to the extent necessary for an enabling disclosure and complete description of the present invention.
Reciprocating piston pumps of this type utilize elastomeric seals at various locations. The '285 patent, for example, discloses the use of a sliding seal 33. In certain situations, such seals may become broken or damaged, allowing fragments thereof to enter the stream of food product moving through the system. Until the present invention, no satisfactory way of achieving an early detection of such elastomeric seal fragments in the product has been available. Consequently, if it is discovered during clean-up operations at the end of the day that one of the seals has been damaged, the entire day's production of food product has to be scrapped. This can be an enormous amount of material, considering that modern food pumps are capable of a throughput on the order of 30,000 pounds of product per hour.
Accordingly, it would be desirable to have an early detection means as part of the processing system itself which could detect fragments of the elastomeric seal almost immediately after they are released into the product such that the system could be quickly shut down and the problem attended to before inordinate amounts of the fragment-containing product are produced. However, elastomeric particles or fragments are extremely difficult to detect in a manner that is economically practical. While detection devices utilizing X-rays are commercially available to serve this purpose, they are extremely expensive to the extent that their use has thus far been largely cost-prohibitive.
Various types of metal detectors are currently commercially available for use with food processing systems. Such detectors are used to discover fragments or chunks of metal in the product flow and, in many cases, to cause the offending product to be diverted from the main product stream until the problem is cleared up.
However, metal detectors detect metal, not elastomeric materials. Therefore, to date they have not been used to solve the problem of early detection of fragmenting elastomeric seals.